Selecting system



A. F. DIXON. SELECTING SYSTEM. APPLICATION FILED Aue.1. m1.

1,328,986. Pamnted Jan. 27, 1920.

UNITED STATES PATENT OFFICE.

AMOS F. DIXON, OF NEWARK, NEW JERSEY, .ASSIGrNOR TO WESTEItN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SELECTING SYSTEM.

Specification of Letters Patent.

Patented Jan. 27, 1920.

Application filed August 1, 1917. Serial No. 183,892.

To all whom it may concern:

Be it known that 1, Autos F. DIXON, a citi zen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Selecting Systems, of which the following is a full, clear, concise, and exact description.

This invention relatesto selective signaling and more particularly to printing telegraphy wherein the various characters of a messa e to be transmitted are represented by di erent permutations of a definite number of current impulses.

The invention is primarily suited to the requirements of single channel operation as distinguished from multiplex operation. In multiplex operation, each transmitting and receiving set is connected to line for only a portion of the time so that sufiicient time is available, after the setting up of any one selection, to print the character thus selected before the line again comes within the control of that set. In single channel operation, however, the line is continuously under the control of one transmitting and receiving set so that, in order to efi'ect economy in line operation, it becomes necessary to provide some sort of overlap arrangement whereby a new selection may be set up before the printing of the character previously selected has been completed.

The present invention provides an arrangement of this sort which is suitable for use in a receiving system, and one which is primarily adapted to use inconnection with the transmitting system disclosed in my copending application, Serial No. 183,891 filed August 1 1917, though obviously applicable to use with any transmitter sending out a similar code.

The invention further provides an adaptation to the requirements of single channel operation of the improved synchronizing system of my copending application, Serial No. 869,784 filed November 2, 1914, and issued Oct. 1, 1918, as Patent No. 1,280,423;

A better understanding of the invention will be had by reference to the accompanying drawing in which 2 represents a distributer, preferably of the rotary type, but here' receiving face 4 connected to the receiver R.

Only that part of the system which is con be understood that, asthe brush arm (not 7 shown) of the distributor rotates, the brush 5 will establish an electrical connection between successive segments and their respective receiving bars. Control segments 30 and 31 are also provided, one for each group of receiving segments, and are so arranged that they will alternately be connected by brush 6 to their common bar 32, for the purpose hereinafter to be set forth.

The systemherein described is arranged to work with the five impulse Baudot code in which each character or signal to be transmitted is represented by a definite combination of positive and negative impulses. In such systems, the positive impulses are customarily spoken of as marking impulses and the negative impulses are spoken of as spacing and spacing impulses will be opposite to those of the preceding series of impulses' If, for example, the letter B is to be transmitted, it would, in one instance, be represented by a positive impulse, followed by two negative impulses, followed by two positive impulses. If, now, the letter immedi ately following were also B,this letter would then be represented by a negative impulse, followed by twopositive impulses, followed by two negative impulses. This arrangement is used for the purpose of maintaining synchronism between the distributors at the two ends of the line, particularly during such time as no message signals are bein sent to the line. During such idle perio spacing impulses alone are transmitted, and,

inasmuch as the polarity of the spacing impulses is alternating in character, the line relay 11 will be intermittently operated,

thereby opening and closing the primary circuit of transformer 45, which controls the synchronizing apparatus in the manner described in my application, Serial No. 869,784, filed November 2, 1914, above referred to.

Let us now consider the operations attend ing the receipt of impulses representing the letter B, which, as seen above, may be represented by a positive impulse, followed by two negative impulses, followed by two positive impulses. ters at the two ends of the line are so synchronized that, when the first impulse is re ceived, the brush 5 will bridge the gap between segment 12 and bar 7. The first impulse being positive, relay 11 Will operate, pulling up its armature 10. A circuit will thus be established from grounded battery 9, over conductor 33, bar 1 brush 5, segment 12, to ground, through relay 16. Relay 16 operates, establishing a holding circuit, for itself from battery 34, over conductor 36. Contact a l of relay 16 will also be closed to prepare a circuit for the selecting magnet 27. The second impulse will be received as brush 5 passes on to segment 14. This impulse being negative, the relay 11 does not operate. Consequently battery 5) is not connected to the bar 7, and relay 17, which is connected to segment let, is not operated. When the third impulse is received, the brush 5 will cover segment 18. This impulse, being negative, relay 11 does not opcrate, so that selecting magnet 24, which is directly connected to segment 18, is not actuated. Simultaneously with the receipt of the third impulse, brush 6 will be inposition to connect segment 30 to bar 32, thus completing a circuit from grounded battery 38, to ground, through selecting magnet 27 and overlap relay 29 in parallel. Selecting magnet 27 will thus be actuated. Relay 29 also operates to open the holding circuit of relay 16. Relay 29 is preferably made slowacting, so as to insure the prior actuation of magnet 27. The fourth impulse being positive, the actuation of relay l1 completes a circuit from grounded battery 9, over conductor 33, bar 7, brush 5, segment 20, to ground through selecting magnet 25, which will then operate. In a similar manner, magnet 26 will be actuated as bar 5 covers segment 22 upon the receipt of the fifth (a positive) impulse.

l Vhen the brush 5 is working over the second group of segments, it will be seen that battery 9 is connected to bar 8 by way of conductor 42 when relay 11 is in its unactuated or normal condition. Consequently, in order that the incoming impulses may be marking impulses, they must be of negative polarity instead of positive polarity, as in the case of the first group of segments. Consequently, it will be seen that a negative impulse, followed by two positive im- Assuming that the distribu ments, a line relay pulses, followed by two negative impulses will, when the distributor arm is wor over the second group of segments, pro' the same selective actuation of the select magnets 27, and 26 as that previous traced in connection with the first group oi segments.

Referring back to relays l6 and 1?, will be seen that these relays function to store up the first two impulses received, and to prevent the effect of these impulses from being transmitted to the magnets 2'? and 28 until the receipt of the third impulse. This interval, corresponding to the duration of the first and second impulses, is made use of tocomplete the printing of the character selected by the previous series of impulses. It will be obvious that the printing interval may be lengthened by providing in the circuit of the magnet 24, a relay similar to relays l6 and 17. In such event, it would naturally follow that control segments 30 and 31 of the distributer would. be so located as to be placed in circuit with the bar 32 upon the receipt of the fourth impulse. I

What is claimed is:

1. A. selecting system comprising a istributing apparatus provided with a plurality of groups of switch contacts, a single group of selecting magnets common to said groups of contacts and arranged to be op erated in various combinations for selection purposes, and means responsive to line current impulses for rendering said switch contacts successively effective to provide operating circuits for said selecting magnets.

2. A selecting system comprising a rotary distributer having two groups of segments, a single group of selecting magnets common to said be operated in various permutations for selection purposes, and means responsive to line current impulses for rendering said groups of segments alternately effective to provide opera-ting circuits for said selecting magnets.

3. In a selecting system, a receiving distributor having a plurality of groups of seg normally adapted to sup ply current to one group of segments and adapted when operated to supply current to another group of segments, and selecting mechanism responsive to both of said groups of segments and adapted to be operated in various combinations for effecting the de sired selection.

4. In a selecting system, a receiving distributer having two similar groups of segments, means responsive to l'ne current impulses for supplying current to said distribnter, selecting magnets responsive to current impulses from either set of segments, means intermediate said selecting magnets and said distributor for storing up some of said impulses, and a relay under the groups of segments and arranged to rec control of said distributer for transferring said stored up impulses to their respective selecting magnets.

5. In a selecting system, a receiving distributer havin two similar groups of segments, a line re ay adapted normally to supply current to one group of segments and when operated to supply current to the other group of segments, selecting magnets responsive to combinations of current impulses 10 from either group of segments, and means controlled by said distributer for delaying the effect of current impulses from some of said segments on their respective selecting magnets. 15 In Witness whereof I hereunto subscribe my name this 30th day of July, A. D. 1917.

AMOS F. DIXON. 

